Blower assembly for a vehicle

ABSTRACT

A blower assembly includes a housing having a scrolled wall, a motor having an output shaft extending within the housing, an impeller positioned within the housing and mounted to the output shaft for creating an airflow along an airflow path within the housing, an airflow outlet, and a scroll cut-off. The scroll cut-off forms a substantially continuous surface with the scrolled wall at a downstream end and with the airflow outlet at an upstream end, along the airflow path, in a first position. The blower assembly also includes an actuator for moving the scroll cut-off along a projection extending from the scrolled wall adjacent the downstream end of the scroll cut-off from the first position to a second position for reducing the airflow. The scroll cut-off may include more than one member.

TECHNICAL FIELD

This document relates generally to blower assemblies used in a vehicle, and more specifically to tuneable blower assemblies associated with heating, ventilation, and air conditioning (HVAC) systems.

BACKGROUND

Blower assemblies are a common component of vehicle HVAC systems and are designed for maximum efficiency/airflow when operated in commonly known re-circulating and fresh modes. In heater mode within the fresh mode, however, the airflow volume can hinder optimal heating performance within the vehicle by over cooling the engine. As a result, the amount of heated coolant available may not be enough to warm-up the passenger compartment to a desired temperature. Even more, the noise level within the passenger compartment in this mode can reach unsatisfying levels due to the large volume of air moving through typically smaller heat passages and outlets. Accordingly, a need exists for a blower assembly that is tunable or adjustable such that a desired airflow volume can be delivered for all modes of operation including the re-circulating and heater mode combination.

While various solutions to this problem exist, each such solution has its own drawbacks. For example, reducing or restricting the airflow volume in heater mode may be accomplished by reducing the speed of the motor/impeller creating the airflow. In this instance, however, adding such restrictions to control heater airflow volume tends to increase turbulence and noise, vibration, and harshness which are equally untenable.

Alternatively, a maximum voltage applied to the motor/impeller may be clipped or limited thus reducing the maximum airflow volume. While the maximum airflow volume may be appropriately reduced using this approach, a minimum voltage applied to the motor/impeller still results in an airflow volume that is greater than what the occupant wants/needs. The minimum voltage is linked to minimum rotations per minute of the motor, and results in an excessive supply of the heated air to warm-up the passenger compartment to the desired temperature. Even more, the steps between desired settings of high speed and low speed become compressed to the point that an occupant of the vehicle may be unable to discern any difference between the selected settings.

Another method of tuning the blower assembly such that the desired airflow volume can be delivered for all modes of operation is to adjust the scroll cut-off of the blower assembly. One manner of adjusting the scroll cut-off of a blower assembly is described in U.S. Pat. No. 1,056,813 to McLean. McLean desired to use a volume blower with a large volume between a scroll wall of a blower housing and a wheel (or impeller) as a pressure blower in some instances by controlling the point of cut-off or minimum distance between the blower housing/scroll wall and periphery of the wheel. In McLean's blower assembly, a scroll cut-off is hingedly connected to the scroll wall of the blower housing allowing the scroll cut-off to pivot about a point of attachment. A horizontal portion of the scroll cut-off overlapped an airflow outlet or discharge duct of the blower assembly, and the horizontal portion generally traversed the airflow outlet. A governor was used to adjust the minimum distance between the blower housing/scroll wall and periphery of the wheel dependent upon the speed of the motor.

Another inventor determined a different way of adjusting the scroll cut-off of a blower assembly. Japanese Patent No. 2003042097A describes an adjustment to a distance or air gap between a blower housing/scroll wall and a periphery of a wheel in blower assemblies used in vehicles. The invention is designed to overcome issues involving low frequency noise created when air blown from a centrifugal fan flows backwards into the fan due to high pressure in an air conditioning duct in a foot or a defrost mode of operation. In the blower assembly, a movable nose or scroll cut-off is provided that is pulled by a cable attached to mode selection levers. The scroll cut-off translates along a scroll wall of a housing of the blower assembly. In other modes, the cable pushes the nose or scroll cut-off back along the scroll wall toward the fan to decrease the air gap in the remaining modes of operation. The patent further teaches use of linkages in place of the cable that are actuated to move the scroll cut-off dependent upon a pressure sensor positioned to sense pressure at an airflow outlet. Another discussed alternative, is to attach the scroll cut-off to the scroll wall allowing the scroll cut-off to pivot outward when pulled by the cable thereby altering the size of the air gap. This approach is similar to the McLean approach.

This document relates to a blower assembly having a scroll cut-off that is adjustable using an actuator so that a desired airflow volume can be delivered for all modes of operation in the vehicle. Advantageously, this allows for the vehicle operator to utilize the blower assembly even in the re-circulating and heater modes. Heretofore, the rate of airflow in these modes was too high resulting in an inability to warm-up the passenger compartment to a desired temperature. Even more, the present design avoids the need for cables and/or linkages between the blower assembly and dash mounted controls, and does not result in increased turbulence and noise, vibration, and harshness.

SUMMARY

In accordance with the purposes and benefits described herein, a blower assembly is provided. The blower assembly may be broadly described as comprising a housing having a scrolled wall, a motor having an output shaft extending within the housing, an impeller positioned within the housing and mounted to the output shaft for creating an airflow along an airflow path within the housing, an airflow outlet, and a scroll cut-off. The scroll cut-off forms a substantially continuous surface with the scrolled wall at a downstream end and with the airflow outlet at an upstream end, along the airflow path, in a first position. The blower assembly also includes an actuator for moving the scroll cut-off along a projection extending from the scrolled wall adjacent the downstream end of the scroll cut-off from the first position to a second position for reducing the airflow.

In one possible embodiment, the second position is adjacent a distal end of said projection. In another embodiment, the scroll cut-off and the impeller define an air gap having a minimum distance in the first position. In yet another possible embodiment, the air gap defined by the scroll cut-off and the impeller has a maximum distance in the second position.

In another possible embodiment, the motor and the output shaft are positioned within the housing.

In one possible embodiment, a downstream end of the scroll cut-off moves along the airflow outlet from the first position to the second position.

In another possible embodiment, the scroll cut-off includes an upstream member and a downstream member which together form the substantially continuous surface with the scrolled wall and the airflow outlet, along the airflow path, in the first position.

In still another, a second projection extends from the housing, the actuator moves the downstream member of the scroll cut-off along the projection and the second projection from the first position to a second position for reducing the airflow. In another possible embodiment, the second position is adjacent a distal end of the projection.

In accordance with an additional aspect, a blower assembly comprises a housing having a scrolled wall, a motor having an output shaft extending within the housing, an impeller positioned within the housing and mounted to the output shaft for creating an airflow along an airflow path within the housing, an airflow outlet, at least two members forming a substantially continuous surface with the scrolled wall at a downstream end and the air flow outlet at an upstream end, along the airflow path, in a first position, a first projection extending from the scrolled wall adjacent the upstream end of the at least two members and a second projection extending from the housing adjacent the downstream end of the at least two members, and an actuator for moving at least one of the at least two members along the first and second projections from the first position to a second position for reducing the airflow.

In one other possible embodiment, the second position is adjacent a distal end of at least one of the first and second projections. In another, an upstream member of the the at least two members and the impeller define an air gap having a minimum distance in the first position.

In still another possible embodiment, the upstream member of the at least two members is moved by the actuator, and a downstream member is static.

In other possible embodiments, the blower assemblies described above are incorporated into a vehicle.

In accordance with another aspect, a method of changing a rate of airflow in a blower assembly is provided. The method may be broadly described as comprising the steps of: (a) creating an airflow using an impeller positioned within a housing having a scrolled wall; (b) establishing an air gap between a scroll cut-off in a first position and the impeller, the air gap determining the rate of the airflow; and (c) adjusting the air gap to affect the rate of airflow by moving the scroll cut-off along a projection extending from the scrolled wall adjacent a downstream end of the scroll cut-off from the first position to a second position.

In one possible embodiment, the scroll cut-off may form a substantially continuous surface with the scrolled wall at the downstream end and an air flow outlet at an upstream end in the first position such that the established air gap is minimized and the airflow rate is maximized. In another possible embodiment, the downstream end of the scroll cut-off is adjacent a distal end of said projection in the second position such that the established air gap is maximized and the airflow rate is minimized.

In still another possible embodiment, the scroll cut-off includes an upstream member and a downstream member which together form the substantially continuous surface with the scrolled wall and the airflow outlet in the first position, and the step of adjusting the air gap includes moving at least one of said upstream and downstream members of the scroll cut-off from the first position to a second position.

In the following description, there are shown and described several preferred embodiments of the blower assembly and the related method. As it should be realized, the assemblies and method are capable of other, different embodiments and their several details are capable of modification in various, obvious aspects all without departing from the assemblies and method as set forth and described in the following claims. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The accompanying drawing figures incorporated herein and forming a part of the specification, illustrate several aspects of the blower assembly and together with the description serve to explain certain principles thereof. In the drawing figures:

FIG. 1 is a perspective view of a blower assembly;

FIG. 2 is a front plan view of the blower assembly;

FIG. 3 is a partial cross-sectional view showing the blower assembly and, in particular, an air flow within an air path and movement of a scroll cut-off along a projection of a scrolled wall; and

FIG. 4 is a partial cross-sectional view of another embodiment showing a blower assembly and, in particular, an air flow within an air path and movement of a scroll cut-off having upstream and downstream members along a projection of a scrolled wall.

Reference will now be made in detail to the present embodiments of the blower assembly and the related method, examples of which are illustrated in the accompanying drawing figures, wherein like numerals are used to represent like elements.

DETAILED DESCRIPTION

Reference is now made to FIGS. 1 and 2 which broadly illustrate an embodiment of a blower assembly 10 having a housing 12 including a scrolled wall 14 and side walls 16, 18. The housing is made of suitable rigid plastic materials in the present embodiment, such as, polypropylene or the like through injection, blow molding, etc. Stamped metal components could likewise be used however. An impeller 20 is positioned within the housing 12 and mounted on an output shaft 22 of a motor 24. Air is drawn into the impeller 20 through an aperture 17 in side wall 16. As shown in FIG. 2, the motor 24 in the present embodiment is mounted to the housing 12 and output shaft 22 extends into the housing where the impeller 20 is mounted. In one possible embodiment, the motor may be mounted within the housing and may even be positioned within the shaft that rotates the impeller, in order to limit the footprint of the blower assembly, as is known in the art.

In operation, motor 24 rotates output shaft 22 which in turn rotates the impeller 20 creating an airflow (generally shown by arrows 26) along an airflow path within the housing 12. The airflow 26 is generated by movement of the impeller 20 within the housing 12. The airflow 26 travels from the impeller 20 through an air gap (A) adjacent a scroll cut-off 28 within the airflow path. The scroll cut-off 28, like the housing 12, is a molded polypropylene, however, other materials may be utilized for the scroll cut-off as well. The airflow 26 continues around the scrolled wall 14 of the housing 12 before exiting the housing at an airflow outlet 30. The airflow outlet 30 may be attached to the housing 12, or may be integrally molded with the housing.

As shown in FIG. 3, the distance between the impeller 20 and the scroll cut-off 28 defines air gap (A) through which the airflow 26 travels. As is known in the art, that distance, or the size of the air gap (A), affects the rate of the airflow as it travels along the airflow path and exits the housing 12 at the airflow outlet 30. Altering the position of the scroll cut-off 28 relative the impeller 20 increases or decreases the rate of the airflow 26.

In the present embodiment, actuator 32 is a vacuum actuator and is mounted to the housing 12 for moving the scroll cut-off 28. As shown by action arrow B in FIG. 3, the scroll cut-off 28 is moved along a projection 34 extending from the housing. The projection 34 extends from the housing 12 adjacent an upstream end of the scroll cut-off 28, and the projection 34 in the described embodiment generally finger-shaped and integrally molded with the housing 12. The projection 34, however, may be any shape or thickness, integrally molded with the housing 12, or otherwise, so long as the projection provides a surface along which the scroll cut-off 28 may travel. Also, the actuator 32 may be driven utilizing a vacuum source, an electrical source, a pneumatic source, or even through linkages.

In FIG. 3, the scroll cut-off 28 is shown in dashed lines in a first position where the scroll cut-off forms a substantially continuous surface with the scrolled wall 14 at an upstream end of the airflow path and the airflow outlet 30 at a downstream end of the airflow path. In the first position, the air gap (A) between the impeller and the scroll cut-off 28 is a minimum distance and the rate of airflow 26 is at a maximum.

When it is desired to lower the rate of airflow 26 from the maximum rate, without changing the speed of the motor 24/impeller 20, the actuator 32 is energized to move the scroll cut-off 28 from the first position to a second position such that the distance between the impeller 20 and the scroll cut-off 28, i.e., the air gap (A), is increased. The rate of the airflow 26 can be controlled to a desired rate between the maximum rate when the air gap (A) is a minimum distance, in the first position, and a minimum rate when the air gap (A) is a maximum distance in a second position.

The scroll cut-off 28 is shown in dashed lines in the first position and in solid lines in the second position in FIG. 3. In this position, an upstream end 36 of the scroll cut-off 28 is adjacent a distal end 38 of the projection 34. In the present embodiment, the scroll cut-off 28 moves linearly as shown by action arrow B between the first and second positions and a downstream end 40 of the scroll cut-off moves along the airflow outlet 30.

In another possible embodiment shown in FIG. 4, the scroll cut-off 28 includes an upstream member 42 and a downstream member 44 which together form the substantially continuous surface with the scrolled wall 14 and the airflow outlet 30, along the airflow path, in the first position. In this embodiment, a second projection 46 extends from housing 12.

As exemplified by the dashed line 48, the downstream member 44 of the scroll cut-off may extend to a position adjacent a distal end 50 of the second projection 46. Alternatively, the downstream member 44 may have a thickness similar to the upstream member 42 causing the length of the second projection 46 to be extended from the length shown. Even more, the downstream member 44, second projection 46, housing 12 and airflow outlet 30 may all be integrally molded in essentially any shape so long as surface 52 extends between the first and second positions, and surface 54 forms a portion of the substantially continuous surface described above.

In this embodiment, the actuator 32 moves the upstream scroll cut-off member 42 along the first and second projections 34, 46 from a first position shown in dashed lines to a second position shown in solid lines for reducing the rate of airflow. As with the first described embodiment, the actuator 32 may move the upstream scroll cut-off member 42 to an intermediary position, thereby adjusting the rate of airflow between a maximum and a minimum, as well.

The maximum rate of airflow is achieved where the upstream scroll cut-off member 42 is in the first position and the air gap (A) has a minimum distance. The minimum rate of airflow is achieved in the second position where the upstream scroll cut-off member 42 is adjacent a distal end 38 of the first projection 34. The upstream scroll cut-off member 42 may also be adjacent a distal end 50 of the second projection 46 in this second position.

In another aspect of the invention, a method of changing a rate of airflow in a blower assembly 10 includes the steps of creating an airflow 26 using an impeller 20 positioned within a housing 12 having a scrolled wall 14, establishing an air gap (A) between a scroll cut-off 28 in a first position and the impeller, and adjusting the air gap to affect the rate of airflow by moving the scroll cut-off along a projection 34 extending from the scrolled wall adjacent a downstream end 40 of the scroll cut-off from the first position to a second position.

The airflow 26 is created by driving the impeller 20 with a motor 24 such that the impeller rotates creating a flow of air within the housing 12. The rate of airflow 26 is determined by the air gap (A) which is the distance between the scroll cut-off 28 and the impeller 20 in the first position shown in dashed lines in FIG. 3. The air gap (A) is established by actuating the scroll cut-off 28 to move the scroll cut-off to a desired position between or including the first position and second position (shown in solid lines in FIG. 2). Once the desired position is established creating a desired rate of airflow, the air gap (A) may be adjusted to affect the rate of airflow. The air gap (A) is adjusted by moving the scroll cut-off to a different position between or including the first and second positions.

If the air gap (A) is established at a midpoint between the first and second positions, then the actuator 32 would move the scroll cut-off toward the second position in order to decrease the rate of air flow by widening the air gap (A). Conversely, the actuator 32 would move the scroll cut-off toward the first position in order to increase the rate of air flow by lessening the air gap (A).

In summary, numerous benefits result from providing a blower assembly having a scroll cut-off that is adjustable using an actuator so that a desired airflow volume can be delivered for all modes of operation in the vehicle. This allows for the vehicle operator to utilize the blower assembly even in the re-circulating and heater modes. Heretofore, the rate of airflow in these modes was too high resulting in an inability to warm-up the passenger compartment to a desired temperature.

The foregoing has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Obvious modifications and variations are possible in light of the above teachings. All such modifications and variations are within the scope of the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled. 

What is claimed:
 1. A blower assembly, comprising: a housing having a scrolled wall; a motor having an output shaft extending within said housing; an impeller positioned within said housing and mounted to said output shaft for creating an airflow along an airflow path within said housing; an airflow outlet; a scroll cut-off forming a substantially continuous surface with said scrolled wall at a downstream end and with said airflow outlet at an upstream end, along the airflow path, in a first position; a projection extending from said scrolled wall adjacent said downstream end of said scroll cut-off; and an actuator for moving said scroll cut-off along said projection from the first position to a second position for reducing the airflow.
 2. The blower assembly of claim 1, wherein the second position is adjacent a distal end of said projection.
 3. The blower assembly of claim 1, wherein said scroll cut-off and said impeller define an air gap having a minimum distance in the first position.
 4. The blower assembly of claim 3, wherein the air gap defined by said scroll cut-off and said impeller has a maximum distance in the second position.
 5. The blower assembly of claim 1, wherein said motor and said output shaft are positioned within said housing.
 6. The blower assembly of claim 1, wherein a downstream end of said scroll cut-off moves along said airflow outlet from the first position to the second position.
 7. The blower assembly of claim 1, wherein said scroll cut-off includes an upstream member and a downstream member which together form the substantially continuous surface with said scrolled wall and said airflow outlet, along the airflow path, in the first position.
 8. The blower assembly of claim 7, further comprising a second projection extending from said housing; and wherein said actuator moves said downstream member of said scroll cut-off along said projection and said second projection from the first position to a second position for reducing the airflow.
 9. The blower assembly of claim 8, wherein the second position is adjacent a distal end of said projection.
 10. The blower assembly of claim 8, wherein said scroll cut-off and said impeller define an air gap having a minimum distance in the first position.
 11. A vehicle incorporating the blower assembly of claim
 1. 12. A blower assembly, comprising: a housing having a scrolled wall; a motor having an output shaft extending within said housing; an impeller positioned within said housing and mounted to said output shaft for creating an airflow along an airflow path within said housing; an airflow outlet; at least two members forming a substantially continuous surface with said scrolled wall at a downstream end and said air flow outlet at an upstream end, along the airflow path, in a first position; a first projection extending from said scrolled wall adjacent said upstream end of said at least two members and a second projection extending from said housing adjacent said downstream end of said at least two members; and an actuator for moving at least one of said at least two members along said first and second projections from the first position to a second position for reducing the airflow.
 13. The blower assembly of claim 12, wherein the second position is adjacent a distal end of at least one of said first and second projections.
 14. The blower assembly of claim 12, wherein an upstream member of said at least two members and said impeller define an air gap having a minimum distance in the first position.
 15. The blower assembly of claim 12, wherein the upstream member of said at least two members is moved by said actuator, and a downstream member is static.
 16. A vehicle incorporating the blower assembly of claim
 12. 17. A method of changing a rate of airflow in a blower assembly comprising the steps of: creating an airflow using an impeller positioned within a housing having a scrolled wall; establishing an air gap between a scroll cut-off in a first position and said impeller, said air gap determining the rate of the airflow; and adjusting the air gap to affect the rate of airflow by moving said scroll cut-off along a projection extending from said scrolled wall adjacent a downstream end of said scroll cut-off from the first position to a second position.
 18. The method of changing an airflow rate in a blower assembly of claim 17, wherein said scroll cut-off forms a substantially continuous surface with said scrolled wall at the downstream end and an air flow outlet at an upstream end in the first position such that the established air gap is minimized and the airflow rate is maximized.
 19. The method of changing an airflow rate in a blower assembly of claim 18, wherein said downstream end of said scroll cut-off is adjacent a distal end of said projection in the second position such that the established air gap is maximized and the airflow rate is minimized.
 20. The method of changing an airflow rate in a blower assembly of claim 17, wherein said scroll cut-off includes an upstream member and a downstream member which together form the substantially continuous surface with said scrolled wall and said airflow outlet in the first position, and the step of adjusting the air gap includes moving at least one of said upstream and downstream members of said scroll cut-off from the first position to a second position. 